staging: iio: adis16240: add blank line before struct definition

Add a blank line before starting structure definition as per coding
style guidelines. Issue reported by checkpatch script.

Acked-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
Link: https://lore.kernel.org/r/20201011104800.GA29412@ubuntu204


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>